/*=========================================================================

  Program:   ORFEO Toolbox
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


  Copyright (c) Centre National d'Etudes Spatiales. All rights reserved.
  See OTBCopyright.txt for details.

  Copyright (c) Institut Telecom / Telecom Bretagne. All rights reserved.
  See ITCopyright.txt for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/

#ifndef __otbEuclideanDistanceMetricWithMissingValuePow2_h
#define __otbEuclideanDistanceMetricWithMissingValuePow2_h

#include "itkEuclideanDistanceMetric.h"

namespace otb {

namespace Statistics {

/** \class EuclideanDistanceMetricWithMissingValuePow2
 * \brief Euclidean comparison distance function facing missing value. The square root is not performed in this class.
 *
 * This class is derived from EuclideanDistanceMetric class. In addition
 * to the initial Evaluate method, the class does not perform calculation
 * when a component does not contain any data. The 'no data' case is perform through the \code SetToMissingValue() \endcode
 * which performs a \code Nan \endcode affectation.
 *
 * The class can be templated over any container that holds data elements, as
 * for template of EuclideanDistanceMetric.
 *
 * The only restriction is that elements have to support NaN values.
 *
 * \sa EuclideanDistanceMetric
 * \sa EuclideanDistanceMetricWithMissingValue
 *
 * \ingroup OTBImageManipulation
 */
template<class TVector>
class ITK_EXPORT EuclideanDistanceMetricWithMissingValuePow2 :
  public itk::Statistics::EuclideanDistanceMetric<TVector>
{
public:
  /** Standard "Self" typedef. */
  typedef EuclideanDistanceMetricWithMissingValuePow2          Self;
  typedef itk::Statistics::EuclideanDistanceMetric<TVector>    Superclass;
  typedef itk::SmartPointer<Self>                        Pointer;
  typedef itk::SmartPointer<const Self>                  ConstPointer;
  typedef typename Superclass::MeasurementVectorSizeType MeasurementVectorSizeType;

  /** Run-time type information (and related methods). */
  itkTypeMacro(EuclideanDistanceMetricWithMissingValuePow2, EuclideanDistanceMetric);

  /** Method for creation through the object factory. */
  itkNewMacro(Self);

  /** Type of the component of a vector */
  typedef typename TVector::ValueType ValueType;

  /** Gets the distance between the origin and x */
  double Evaluate(const TVector& x) const;

  /** Gets the distance between x1 and x2 */
  double Evaluate(const TVector& x1, const TVector& x2) const;

  /** Gets the cooridnate distance between a and b. NOTE: a and b
  * should be type of component */
  double Evaluate(const ValueType& a, const ValueType& b) const;

  /** Returns true if the distance between x and the origin is less
  * than radius */
  bool IsWithinRange(const TVector& x, const double radius) const
  {
    return Superclass::IsWithinRange(x, radius);
  }

  /** Check if a value is NaN or not */
  static bool IsMissingValue(const ValueType& v);

  /** Set a value to Nan */
  static void SetToMissingValue(ValueType& v);

protected:
  EuclideanDistanceMetricWithMissingValuePow2() {}
  virtual ~EuclideanDistanceMetricWithMissingValuePow2() {}
}; // end of class

} // end namespace statistics

} // end namespace otb

#ifndef OTB_MANUAL_INSTANTIATION
#include "otbEuclideanDistanceMetricWithMissingValuePow2.txx"
#endif

#endif
